This invention relates to a drainage channel system which includes sidewall extensions for increasing the length of a continuous and progressive sloping run of the drainage channel system, and a method for extending the continuous slope of a run of a drainage channel system. Drainage channels of the type referred to in this application are open top drainage channels which are used to drain, for example, parking lots, airport runways, taxiways and ramps, and driveways. Such drainage channel systems also are used in various interior drainage applications. Usually, a longitudinally extending grate is set into the open top of the drainage channel.
Both the channel itself and the grate may be constructed of various materials according to various processes to support light, medium or heavy loads. In the particular embodiment discussed in this application, the drainage channels and sidewall extensions are cast of "polyester concrete." Polyester concrete is a concrete aggregate material containing quartz and inert mineral fillers bonded together with polyester resin.
A drainage channel "run" is formed by using cast channel segments having successively higher walls so that when connected together end-to-end in the proper order in a gradually deepening trench they collectively form a run having a 0.6% slope, as described above.
The channel segments are embedded in concrete within a trench which must be properly prepared to receive the channel segments in proper order and with proper slope.
One conventional system of constructing a drainage channel involves the use of 30 interlocking channel segments, each approximately one meter in length with a built-in slope of 0.6%. Accordingly, a single, continuously sloping, uninterrupted run of approximately 30 meters can be constructed simply by interconnecting these channel segments of gradually increasing depth end-to-end. However, in many applications longer runs are necessary. Heretofore, longer runs have been achieved by placing oppositely directed falls adjacent to each other with multiple outlets. Runs have also be extended by interspersing non-sloping channels throughout the length of the run. However, the maximum rate of fluid flow either remains the same, or in some cases is decreased, by using one of these methods.
Of course, a continuous run can be made longer simply by making more and more channel segments, each having a greater depth. However, there are several reasons why one cannot simply increase the depth of the individual channel segments indefinitely. Increasing the number of channel segments increases the number of segments which must be maintained in inventory. In addition, as the sidewalls of the channel segments increase in length, correspondingly more material is used and the finished product is substantially heavier, but nevertheless more subject to breakage during handling. Since such oversized channel segments would be used only in projects calling for a longer than normal run, the cost per unit for such oversized segments would be very high.